AN INVESTIGATION ON THE EFFECT OF ELECTROCHEMICAL ADSORBATES ON PROPERTIES OF ELECTRODEPOSITED NANOCRYSTALLINE Fe–Ni ALLOYS

2013 ◽  
Vol 12 (01) ◽  
pp. 1350002 ◽  
Author(s):  
A. SANATY-ZADEH ◽  
K. RAEISSI ◽  
A. SAIDI
Keyword(s):  
Grain Size ◽  
Current Density ◽  
Cathode Surface ◽  
Iron Hydroxide ◽  
Ni Alloys ◽  
Fe Content ◽  
Iron Nickel ◽  
Current Densities ◽  
Eis Measurements ◽  
Deposition Current Density

Iron–Nickel nanocrystalline alloys were electrodeposited from a simple chloride bath using different current densities. The composition and grain size of deposited alloys were in the range of 29–42% Ni and 8–11 nm, respectively. The alloy deposited at lower current density showed higher microhardness, which is most probably due to its higher Fe content and lower grain size. EIS measurements showed that the iron hydroxide species can be formed and adsorbed onto the cathode surface during the deposition. Such species showed an inhibitive effect not only on Ni ion reduction but also on grain growth. By increasing the deposition current density, the adsorption tendency of iron hydroxide was reduced which caused an increase in grain size and Ni percentage of the alloy produced.

Electroforming and Mechanical Properties of Iron-Nickel Alloy Foil

1979 ◽  
Vol 21 (6) ◽  
pp. 411-417 ◽  
Author(s):  
S. H. F. Lai ◽  
J. A. McGeough
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Hydrogen Embrittlement ◽  
Nickel Alloy ◽  
Current Density ◽  
Nickel Chloride ◽  
Iron Foil ◽  
Alloy Foil ◽  
Iron Nickel ◽  
Current Densities

A method of electroforming smooth, bright, iron-nickel alloy foil, of thickness about 0.1 mm, is developed. The electrolyte, mainly a solution of ferrous chloride and nickel chloride, is operated at a temperature of 95 °C, and at current densities of between 5 and 20 A/dm2. Below that temperature, and at current densities greater than 20 A/dm2, the foil becomes cracked. The amount of nickel co-deposited in the alloy can be increased up to a limit of 6.24 per cent, by reducing the current density and/or increasing the concentration of nickel chloride in the electrolyte. As the nickel content of the foil rises, the material suffers increasingly from hydrogen embrittlement. The main mechanical properties of the alloy foil are more affected by hydrogen embrittlement, the amount of which is influenced by current density and the concentration of nickel chloride, than by changes in grain size. This behaviour is in contrast with that of electroformed iron foil, for which the mechanical properties are largely controlled by the influence of the current density and electrolyte temperature upon its grain size. However, when the other process conditions are held constant, the mechanical properties of the alloy foil behave like the iron foil in decreasing with increasing foil thickness, owing to increases in average grain size.

scholarly journals Effect of deposition current density and annealing temperature on the microstructure and magnetic properties of nanostructured Ni-Fe-W-Cu alloys

2019 ◽  
Vol 51 (2) ◽  
pp. 209-221 ◽  
Author(s):  
Milica Spasojevic ◽  
Dusan Markovic ◽  
Miroslav Spasojevic ◽  
Zoran Vukovic ◽  
Aleksa Maricic ◽  
...  
Keyword(s):  
Current Density ◽  
Amorphous Matrix ◽  
Ammonium Citrate ◽  
High Current ◽  
Cathodic Polarization Curve ◽  
Cu Alloy ◽  
Powder Particles ◽  
Current Densities ◽  
Deposition Current Density ◽  
Microstructure And Magnetic Properties

Ni-Fe-W-Cu alloy powders were obtained by electrodeposition from an ammonium citrate bath at current densities ranging between 70 and 600 mA cm-2. As the deposition current density increased, the contents of Fe and W in the alloy increased, and those of Ni and Cu decreased. The total cathodic polarization curve was recorded, and partial polarization curves for Ni, Fe and W deposition and hydrogen evolution were determined. The current efficiency of alloy deposition was measured. The powders contained an amorphous matrix and FCC nanocrystals of the solid solution of Fe, W and Cu in Ni. At high current densities, small-sized nanocrystals exhibiting high internal microstrain values were formed. Powder particles were dendrite- and cauliflower-shaped. The dendrites had a large number of secondary branches and higher-order branches containing interconnected globules. The density of branches was higher in particles formed at high current densities. The powders formed at high current densities exhibited higher magnetization. Annealing at temperatures up to 460?C resulted in structural relaxation, accompanied by an increase in magnetization. At temperatures above 460?C, amorphous matrix crystallization and FCC crystal growth took place, accompanied by a decrease in magnetization.

CATHODE SURFACE CHANGES IN THE PRESENCE OF GELATIN DURING ELECTRODEPOSITION OF COPPER

1943 ◽  
Vol 21b (6) ◽  
pp. 125-132 ◽  
Author(s):  
W. Gauvin ◽  
C. A. Winkler
Keyword(s):  
Grain Size ◽  
Current Density ◽  
Copper Sulphate ◽  
Cathode Surface ◽  
Active Area ◽  
Cathode Polarization ◽  
Active Centres ◽  
Main Factor ◽  
Surface Changes

Measurements of the cathode polarization during electrodeposition of copper from acid copper sulphate solutions indicate that introduction of gelatin into the electrolyte decreases the area of the cathode available for deposition, or active area, owing to adsorption of gelatin on the active centres. This decrease in area causes an increase in the true current density, with a resulting increase in cathode polarization, the former being assumed the main factor in causing an increase in the rate of nuclear formation and decrease in grain size.

The Influence of Current Density of Electrodeposition on the Electrochemical Properties of Ni-Mo Alloy Coatings

2015 ◽  
Vol 228 ◽  
pp. 269-272 ◽  
Author(s):  
Magdalena Popczyk ◽  
B. Łosiewicz
Keyword(s):  
Current Density ◽  
Room Temperature ◽  
Catalytic Properties ◽  
Sodium Molybdate ◽  
Nickel Chloride ◽  
Intrinsic Activity ◽  
Nickel Plating ◽  
Plating Bath ◽  
Eis Measurements ◽  
Deposition Current Density

The Ni-Mo alloy coatings with a high content of Mo up to 44.5 at.%, were prepared by galvanostatic electrodeposition in the range of deposition current density, jdep, from-30 to-240 mA cm-2 from the nickel plating bath containing potassium pyrophosphate, nickel chloride, sodium molybdate, and sodium bicarbonate. Investigations of hydrogen evolution reaction (HER) were carried out in 5 M KOH solution at room temperature using steady-state polarization and electrochemical impedancy spectroscopy (EIS) measurements. It was found that for the Ni-Mo alloy coatings, the increase in their catalytic properties towards the HER with the increase in the value of jdep of the coatings, was due to the intrinsic activity.

scholarly journals The phase structure and morphology of electrodeposited nickel-cobalt alloy powders

2011 ◽  
Vol 43 (3) ◽  
pp. 313-326 ◽  
Author(s):  
M. Spasojevic ◽  
L. Ribic-Zelenovic ◽  
A. Maricic
Keyword(s):  
Current Density ◽  
Amorphous Powder ◽  
Nanocrystalline Powders ◽  
Content Increase ◽  
Nickel Powders ◽  
Electrodeposited Nickel ◽  
Current Densities ◽  
Two Phases ◽  
A Current ◽  
Deposition Current Density

Cobalt and nickel powders of three different compositions: Ni0.8Co0.2, Ni0.55Co0.45 and Ni0.2Co0.8 were obtained by electrodeposition from an ammonium chloride-sulphate solution. It was shown that the microstructure and morphology of the powders depended on the deposition current density as well as on the bath composition. Amorphous powder of Ni0.8Co0.2 was obtained at the current density higher than 200 mA cm-2, but nanocrystalline powders having the same composition were obtained at current densities lower than 200 mAcm-2. The nanocrystalline powders with lower Ni contents (0.55 and 0.2) obtained at a current density ranging from 40 mA cm-2 to 450 mA cm-2 were solid solutions of two phases, FCC (?-Ni) and HCP (?-Co) ones. The increase of the HCP phase in the powder was a result of both the Co content increase in the powder and decrease of the deposition current density.

Experimental Study of Mechanical Properties of Electroformed Nanocrystalline Ni-Mn Alloys

2008 ◽  
Vol 375-376 ◽  
pp. 148-152
Author(s):  
Jian Ming Yang ◽  
Di Zhu
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Tensile Properties ◽  
Current Density ◽  
Average Current Density ◽  
Mean Grain Size ◽  
Average Current ◽  
Mn Content ◽  
The Mean ◽  
Deposition Current Density

In this paper, the measurements of microhardness and tensile properties are performed to the electroformed Ni-Mn alloys which the mean grain size is near to or less than 100nm. It is studied that the effect of average deposition current density on microhardness and tensile properties of the alloys and the effect of post-electroforming annealing on microhardness of the alloys. The results show that with the increment of average current density, microhardness and strength of the alloys increase and elongation decreases because of the increment of Mn content and the decrement of grain size of the alloys. Microhardness of the alloys are slightly improved after annealing.

Structural Characterization of Electrodeposited Nickel-Iron Alloy Films

2010 ◽  
Vol 654-656 ◽  
pp. 2430-2433 ◽  
Author(s):  
Yusrini Marita ◽  
Iskandar Idris Yaacob
Keyword(s):  
Dislocation Density ◽  
Crystallite Size ◽  
Current Density ◽  
Iron Alloy ◽  
Face Centered Cubic ◽  
Alloy Films ◽  
Nickel Iron ◽  
Current Densities ◽  
Nickel Iron Alloy ◽  
Deposition Current Density

Nickel-iron nanocrystalline alloy films were prepared on copper substrates by electrochemical deposition at various current densities of 6, 9.7, 11.5 and 15.2 A dm-2. X-ray diffraction measurements confirmed that all nickel-iron alloy films formed have face-centered cubic structure. The structural parameters such as the lattice constant, crystallite size, microstrain and dislocation density were determined for the nickel-iron alloy films. The crystallite size of the films reduced from 17 to 12.9 nm when the current densities were decreased. The reduction in crystallite size increased the dislocation density. Magnetic property measurements using alternating gradient magnetometer indicated that these alloys were ferromagnetic. The saturation magnetization Ms of nickel-iron alloy films increased with decreasing deposition current density, which was attributed to the increase of iron content. Nickel-iron alloy film prepared at deposition current density of 6 A dm-2 showed the maximum value of Ms. The coercivity of nickel-iron alloy films increased with decreasing current density, which was likely caused by reduction in crystallite size.

scholarly journals Fe-Ni ALLOY ELECTRODEPOSITION FROM SIMPLE AND COMPLEX TYPE SULFATE ELECTROLYTES CONTAINING Ni/Fe RATIO OF 1 AND 12

2014 ◽  
Vol 44 (1) ◽  
pp. 51-56 ◽  
Author(s):  
M. Moniruzzaman ◽  
K.M. Shorowordi ◽  
A. Azam ◽  
M.F.N. Taufique
Keyword(s):  
Grain Size ◽  
Current Density ◽  
High Current Density ◽  
Complexing Agents ◽  
Alloy Electrodeposition ◽  
Fine Grained ◽  
Ni Alloy ◽  
Iron Nickel ◽  
High Degree ◽  
Density Results

Iron-nickel (Fe-Ni) alloy electrodeposition has been conducted from simple and complex baths having Ni/Fe ratio of 1 and 12. The applied current density varies from 30 to 100 mA/cm2. The coating composition, morphology and microhardness are measured and characterized by SEM/EDX and Shimadzu microhardness tester. The percentage of Ni in the coating increases with increasing current density and the Ni/Fe ratio of electrolytes which is supported by the alloy deposition principle. Fine grained and smooth coating without microcracking is obtained from the complex baths. Complexing agents are supposed to reduce the deposit stress developed during electrodeposition. Increase in Ni/Fe ratio in the bath as well as current density results in decreasing grain size of the deposits. High current density is believed to give rise to a high degree of adatoms at the electrode surface and high degree of adatoms decreases the grain size. Microhardness of the coating increases with the increase of bath Ni/Fe ratio as well as current density of electrodeposition. DOI: http://dx.doi.org/10.3329/jme.v44i1.19498

MAGNETIC PROPERTIES OF NANOCRYSTALLINE Fe–Ni ALLOYS SYNTHESIZED BY DIRECT AND PULSE ELECTRODEPOSITION

2011 ◽  
Vol 25 (15) ◽  
pp. 2031-2038 ◽  
Author(s):  
A. SANATY-ZADEH ◽  
K. RAEISSI ◽  
A. SAIDI
Keyword(s):  
Pulse Current ◽  
Grain Sizes ◽  
Fe Content ◽  
Bcc Structure ◽  
Nanocrystalline Iron ◽  
Iron Nickel ◽  
Current Densities ◽  
Xrd Patterns ◽  
Iron Nickel Alloys ◽  
Fcc Structure

Nanocrystalline iron–nickel alloys are electrodeposited by direct and pulse current densities with the grain sizes between 8–16 nm. XRD patterns showed a variety of structure in alloys from fcc, bcc and mixed (fcc+bcc) by variation of Fe content of alloy. The fcc structure was observed for lower Fe content, dual phase structure for Fe content between 60–70% and bcc structure for higher Fe content. By applying pulse current, an increase in Fe content of alloys was observed. Magnetic property measurements showed a high saturation magnetization for the alloys increased with increase in Fe content and a low coercivity decreased with decrease in grain size for alloys with iron content below 60%.

EFFECT OF SURFACE ON CATHODE POLARIZATION DURING THE ELECTRODEPOSITION OF COPPER

1943 ◽  
Vol 21a (4) ◽  
pp. 37-50 ◽  
Author(s):  
W. Gauvin ◽  
C. A. Winkler
Keyword(s):  
Steady State ◽  
Current Density ◽  
Crystal Size ◽  
Cathode Surface ◽  
Surface Condition ◽  
Metal Structure ◽  
Polarization Current ◽  
Cathode Polarization ◽  
Current Densities ◽  
Effect Of Surface

Measurements in a modified Haring cell have shown that at current densities above approximately 0.6 amp. per dm.2, definite values of the cathode polarization are attained during the electrodeposition of copper from acid copper sulphate solutions, providing sufficient time is allowed for the cathode surface to attain a steady state corresponding to the conditions of electrolysis. At lower current densities, the base metal structure is perpetuated in the deposit, and the cathode polarization will depend upon the surface condition of the electrode initially. The results account for the lack of agreement in polarization values obtained by different workers using the Haring cell, and indicate that crystal size is fundamentally related to true current density, rather than to cathode polarization. A method is outlined for obtaining reproducible cathode-polarization–current-density curves, substantially corresponding to steady state values.

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